1. Field of the Invention
This invention relates to a polymeric concentrate which, when combined with water as a carrier for active pharmaceutical and/or cosmetic components, forms a gel or emulsion of improved stability and resistance to removal by water. The invention also relates to the process for obtaining said concentrate and carrier compositions.
2. Description of the Prior Art
U.S. Pat. Nos. 6,255,421 and 6,566,473 describe single stage, free radical polymerization processes which may involve one or more of the present monomers in an oil solution medium. These polymeric polymers are optionally crosslinked. However, these processes are designed to produce copolymers of graft, block, or random structure which do not provide entrapment of one polymer in the network of a distinctly different polymer. Similarly linear polymeric products are obtained by the bulk polymerization of long chain/short chain acrylate and/or acrylamide monomeric mixtures in oil medium, as described in U.S. patent application Ser. No. 10/350,404, filed on Jan. 23, 2003.
Current research is directed toward improving the stability of the prior polymeric systems and extending water insolubility and resistance to hinder rinse-off of water insoluble acrylate, acrylamide and acrylic polymeric carriers to provide more durable sun blocking compositions and other cosmetic or pharmaceutical formulations in the form of a more durable gel or emulsion carrier.
Accordingly, it is an object of this invention to achieve the above product goals together while providing an economical and commercially feasible process for producing such products.
Another object is to produce a polymer/oil carrier suitable for personal care or pharmaceutical formulations wherein the water resistant polymeric moieties are protected against rinse-off and to obviate the need for frequent applications, as with current sun block or other formulations.
Still another object is to produce a stable water resistant polymer/oil composition of comparatively dense structure for more securely holding active moieties in the carrier/active formulation.
Yet another object is to provide a water resistant polymer/oil carrier with enhanced ability to entrap a wide variety of water soluble and/or water insoluble chemical particles within its structure.
Another object is to provide a highly stable, liquid polymeric network as a carrier capable of containing relatively high loads of active component in a concentrate composition for impregnating pharmaceutical dressings and the like.
These and other objects and advantages of the invention will become apparent from the following description and disclosure.